I think it is strange that he is "adamant" on not taking George to the vet. Is it that he doesn't want to face the fact that he might be really sick? Or is there something else (like he's not his cat and he poofed him years ago)?
Well, I hope the GF will take your advice and suggestions to at least help George in the meantime to be comfortable. And I hope you can eventually get through to your friend/neighbor to get George to the vet.
Good luck!!